Pressure sensing sealing plate

ABSTRACT

An end effector assembly for use with an electrosurgical instrument is provided. The end effector assembly has a pair of opposing jaw members. One or more of the jaw members includes a support base, an electrical jaw lead, and a sealing plate coupled to the electrical jaw lead. The sealing plate has a stainless steel layer and one or more piezoelectric sensors. The jaw member also includes an insulative plate disposed between the support base and the sealing plate.

BACKGROUND

1. Technical Field

The present disclosure relates to an electrosurgical instrument andmethod for sealing tissue. More particularly, the present disclosurerelates to an electrosurgical tool including opposing jaw members havingpressure sensors for determining a seal pressure and controllingoperation of the electrosurgical tool based on the determined sealpressure.

2. Background of the Related Art

Electrosurgical forceps utilize mechanical clamping action along withelectrical energy to effect hemostasis on the clamped tissue. Theforceps (open, laparoscopic or endoscopic) include electrosurgicalsealing plates which apply the electrosurgical energy to the clampedtissue. By controlling the intensity, frequency and duration of theelectrosurgical energy applied through the sealing plates to the tissue,the surgeon can coagulate, cauterize, and/or seal tissue.

Since tissue sealing procedures involve more than simply cauterizingtissue and blood, to create an effective seal the procedures involveprecise control of a variety of factors. In order to affect a properseal in vessels or tissue, it has been determined that two predominantmechanical parameters should be accurately controlled: the pressureapplied to the tissue; and the gap distance between the electrodes(i.e., distance between opposing jaw members when closed about tissue).

Numerous electrosurgical instruments have been proposed in the past forvarious endoscopic surgical procedures. However, most of theseinstruments cauterize or coagulate tissue and do not allow thesufficiently strong tissue fusion of all tissue types. Consequentially,many of the existing instruments generally rely on clamping pressurealone to procure proper sealing thickness and are often not designed totake into account the seal pressure and applying energy to seal thetissue either sinusoidally or based on feedback from the tissue orproperties of the device.

SUMMARY

In an embodiment of the present disclosure, an end effector assemblyincluding a pair of opposing jaw members is provided. One or more of thejaw members includes a support base, an electrical jaw lead, and asealing plate coupled to the electrical jaw lead. The sealing plate hasa stainless steel layer and one or more piezoelectric sensors. The jawmember also includes an insulative plate disposed between the supportbase and the sealing plate.

The insulative plate is a flex circuit having a plastic substrate and acircuit trace having one or more contacts coupled thereto. The one ormore contacts are coupled to one or more piezoelectric sensors. Thecontact may be operatively coupled to a controller via a contact trace.

In another embodiment of the present disclosure, an electrosurgicalinstrument for sealing tissue is provided. The electrosurgicalinstrument may include a housing having at least one shaft that extendstherefrom, a handle assembly operably coupled to the housing, a rotatingassembly operably coupled to and configured to rotate the at least oneshaft and an end effector assembly disposed at a distal end of the atleast one shaft including a pair of opposing jaw members. One or more ofthe jaw members includes a support base, an electrical jaw lead, and asealing plate coupled to the electrical jaw lead. The sealing plate hasa stainless steel layer and one or more piezoelectric sensors. The jawmember also includes an insulative plate disposed between the supportbase and the sealing plate.

The insulative plate is a flex circuit having a plastic substrate and acircuit trace having one or more contacts coupled thereto. The one ormore contacts are coupled to one or more piezoelectric sensors. Thecontact may be operatively coupled to a controller via a contact trace.

In yet another embodiment, a method of constructing a jaw member for anend effector assembly is provided. The method includes creating a sealplate by shaping a stainless steel layer into a seal plate, applying afirst mask to the stainless steel layer, wherein the first mask exposesa portion of the stainless steel layer, etching the exposed portion ofstainless steel layer to create one or more holes in the stainless steellayer and removing the mask. An insulative plate is also created byproviding a plastic substrate, adhering a conductive layer to theplastic substrate, applying a second mask to the conductive layer,wherein the second mask exposes a portion of the conductive layer tooutline one or more circuit traces and one or more contacts, etching theexposed portion of the conductive layer, and removing the mask. Asupport base is provided and the insulative plate is attached to thesupport base and the seal plate is attached on top of the insulativeplate so that the one or more holes of the seal plate overlaps the oneor more contacts of the insulative plate. A piezoelectric sensor iscoupled to the at least one contact of the insulative plate. Thepiezoelectric sensor is disposed in the one or more holes of the sealplate.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of the presentdisclosure will become more apparent in light of the following detaileddescription when taken in conjunction with the accompanying drawings inwhich:

FIG. 1 is a perspective view of an endoscopic bipolar forceps inaccordance with an embodiment of the present disclosure;

FIG. 2 is a perspective view of an open bipolar forceps in accordancewith an embodiment of the present disclosure;

FIGS. 3A and 3B are perspective views of opposing jaw members accordingto an embodiment of the present disclosure;

FIGS. 4A and 4B are exploded views of the opposing jaw members of FIGS.3A and 3B respectively;

FIG. 5A is a top view of a insulation plate according to an embodimentof the present disclosure;

FIG. 5B is a top view of a sealing plate according to an embodiment ofthe present disclosure;

FIG. 6 is a schematic block diagram of an electrosurgical systemaccording to an embodiment of the present disclosure; and

FIG. 7 is a flowchart depicting a sealing method using anelectrosurgical instrument.

DETAILED DESCRIPTION

Particular embodiments of the present disclosure are describedhereinbelow with reference to the accompanying drawings; however, thedisclosed embodiments are merely examples of the disclosure and may beembodied in various forms. Well-known functions or constructions are notdescribed in detail to avoid obscuring the present disclosure inunnecessary detail. Therefore, specific structural and functionaldetails disclosed herein are not to be interpreted as limiting, butmerely as a basis for the claims and as a representative basis forteaching one skilled in the art to variously employ the presentdisclosure in virtually any appropriately detailed structure.

Like reference numerals may refer to similar or identical elementsthroughout the description of the figures. As shown in the drawings anddescribed throughout the following description, as is traditional whenreferring to relative positioning on a surgical instrument, the term“proximal” refers to the end of the apparatus which is closer to theuser and the term “distal” refers to the end of the apparatus which isfurther away from the user. The term “clinician” refers to any medicalprofessional (i.e., doctor, surgeon, nurse, or the like) performing amedical procedure involving the use of embodiments described herein.

As described in more detail below with reference to the accompanyingfigures, the present disclosure is directed the use of piezoelectricsensors in a vessel sealing procedure. More specifically, piezoelectricsensors are used instead of conventional ceramic stop members. Thepiezoelectric sensors provide a seal pressure to a controller thatadjusts the closure pressure of the jaw members according to open loopor closed loop feedback mechanisms. By using piezoelectric sensorsinstead of stop members, jaw members may be made smaller as well asprovide better controlled sealing of certain tissue types or new tissuetypes.

Turning to FIG. 1, an instrument generally identified as forceps 10 isfor use with various surgical procedures and includes a housing 20, ahandle assembly 30, a rotating assembly 80, a trigger assembly 70, andan end effector assembly 100 that mutually cooperate to grasp, seal, anddivide tubular vessels and vascular tissues. Forceps 10 includes a shaft12 that has a distal end 16 dimensioned to mechanically engage the endeffector assembly 100 and a proximal end 14 that mechanically engagesthe housing 20. The end effector assembly 100 includes opposing jawmembers 110 and 120, which cooperate to effectively grasp tissue forsealing purposes. The end effector assembly 100 is a bilateral assembly,i.e., both jaw members 110 and 120 pivot relative to one another about apivot pin 95. Unilateral jaw assemblies may also be contemplated. Thejaw members 110 and 120 are curved to facilitate manipulation of tissueand to provide better “line of sight” for accessing targeted tissues.

Examples of forceps are shown and described in commonly-owned U.S.application Ser. No. 10/369,894 entitled “VESSEL SEALER AND DIVIDER ANDMETHOD MANUFACTURING SAME” and commonly owned U.S. application Ser. No.10/460,926 (now U.S. Pat. No. 7,156,846) entitled “VESSEL SEALER ANDDIVIDER FOR USE WITH SMALL TROCARS AND CANNULAS.

With regard to FIG. 2, an open forceps 200 for use with various surgicalprocedures is shown. Forceps 200 includes a pair of opposing shafts 212a and 212 b having an end effector assembly 230 attached to the distalends 216 a and 216 b thereof, respectively. End effector assembly 230 issimilar in design to end effector assembly 100 and includes pair ofopposing jaw members 232 and 234 that are pivotably connected about apivot pin 265 and which are movable relative to one another to grasptissue. Each shaft 212 a and 212 b includes a handle 215 and 217,respectively, disposed at the proximal end 214 a and 214 b thereof whicheach define a finger hole 215 a and 217 a, respectively, therethroughfor receiving a finger of the user. Finger holes 215 a and 217 afacilitate movement of the shafts 212 a and 212 b relative to oneanother which, in turn, pivot the jaw members 232 and 234 from an openposition wherein the jaw members 232 and 234 are disposed in spacedrelation relative to one another to a clamping or closed positionwherein the jaw members 232 and 234 cooperate to grasp tissuetherebetween.

FIGS. 3A and 3B are perspective views of the opposing jaw members 310and 320. Similar to jaw members 110 and 120, each of the jaw members 310and 320 include: sealing plates 312 and 322, respectively; electricaljaw leads 325 a and 325 b, respectively; and support bases 316 and 326formed as plastic overmolds. Electrical jaw leads 325 a and 325 b supplyenergy to at least one of the opposing jaw members 310 and 320.

Turning to FIGS. 4A and 4B, the opposing jaw members 310 and 320 includesupport bases 316 and 326 that each extend distally from flanges 313 and323, respectively. The support bases 316 and 326 are dimensioned tosupport insulative plates 319′ and 329′, which in turn, supportelectrically conductive sealing plates 312 and 322 thereon. It iscontemplated that sealing plates 312 and 322 may be affixed atop theinsulative plates 319′ and 329′, respectively, and support bases 319 and329, respectively, in any known manner in the art, snap-fit,over-molding, stamping, ultrasonically welded, etc. The support bases319 and 329, insulative plates 319′ and 329′, and sealing plates 312 and322 are encapsulated by the outer insulative housings 316 and 326 by wayof a subsequent overmolding process. The jaw members 310 and 320 areconnected via an ultrasonic weld to electrical jaw leads 325 a and 325b, respectively.

The jaw members 310 and 320 also include proximal flanges 313 and 323extending proximally from the support bases 319 and 329, respectively,each of which includes an elongated angled cam slot 317 and 327,respectively, defined therethrough. The jaw member 320 also includes aseries of piezoelectric sensors 390 disposed on the inner facing surfaceof an electrically conductive sealing plate 312 to define a gap betweenopposing sealing surfaces during sealing and cutting of tissue. In oneembodiment, the gap is between about 0.001″ and 0.006″; however, othersuitable gaps are contemplated by the present disclosure. The series ofpiezoelectric sensors 390 are applied onto the sealing plate 312 duringmanufacturing. The electrically conductive sealing plates 312 and 322and the insulative plates 319′ and 329′ include respectivelongitudinally-oriented knife slots 315 a, 315 a′ and 315 b, 315 b′,respectively, defined therethrough for reciprocation of the knife blade(not shown).

Turning to FIG. 5A, a top view of insulative plate 329′ is shown.Insulative plate 329′ is a flex circuit. Flex circuits are used toassemble electronic circuits by mounting electronic devices on flexibleplastic substrates. Such plastic substrates may include, but are notlimited to, polyimide or polyether ether ketone (PEEK) film. Flexcircuits may also be constructed by screen printing silver or coppercircuits onto polyester. As shown in FIG. 5A insulative plate 329′ has asubstrate 510 having circuit traces 520 formed thereon. Circuit traces520 may be made from copper, silver, or any other electrical conductor.Circuit traces 520 may be formed by any suitable method. For instance,circuit traces 520 may be formed by adhering a conductive layer tosubstrate 510. Using photolithography, a mask outlining circuit traces520 may be formed and then the conductive layer may be etched to leavecircuit traces 520.

Circuit traces 520 include contacts 524 that may be made from copper,silver or any other suitable electrical conductor. Contacts 524 may bemade from the same material as circuit traces 520 or from a materialdifferent from circuit traces 520. Each contact 524 is operativelycoupled to controller 620 (FIG. 6) via contact traces 522. Contacts 524and contact traces 522 are formed using the same techniques that may beused to form circuit traces 524. The location of contacts 524 correspondto the location of piezoelectric sensors 390. Accordingly, whenpiezoelectric sensors 390 determine a seal pressure, piezoelectricsensors 390 provide a signal to controller 620 indicative of the sealpressure via contacts 524 and contact traces 522.

FIG. 5B depicts a top view of seal plate 322. Seal plate 322 is madefrom stainless steel, and as described above, has piezoelectric sensors390 disposed therein in locations 530. Seal plate 322 may be formed byany suitable method. For instance, a layer of stainless steel may beprovided and shaped to form seal plate 322. Then, a photolithographymask is applied to seal plate 322 leaving locations 530 exposed. Anetching solution is applied to seal plate 322 to etch away exposedlocations 530. Then the mask is removed leaving seal plate 322 withlocations 530 etched away. When jaw member 320 is assembled,piezoelectric sensors 390 are placed in locations 530 of seal plate 322and are coupled to contacts 524 of insulative plate 329′. Locations 530may also be formed from other suitable methods, such as punching,drilling, etc.

FIG. 6 shows a schematic block diagram of the generator 600 having acontroller 620, a power supply 627, an RF output stage 628, and a sensormodule 622. The power supply 627 provides DC power to the RF outputstage 628 which then converts the DC power into RF energy and deliversthe RF energy to the instrument 10. The controller 620 includes amicroprocessor 625 having a memory 626 which may be volatile type memory(e.g., RAM) and/or non-volatile type memory (e.g., flash media, diskmedia, etc.). The microprocessor 625 includes an output port connectedto the power supply 627 and/or RF output stage 628 that allows themicroprocessor 625 to control the output of the generator 600 accordingto either open and/or closed control loop schemes.

A closed loop control scheme generally includes a feedback control loopwherein the sensor module 622 provides feedback to the controller 24(e.g., information obtained from one or more sensing mechanisms forsensing various tissue parameters such as tissue impedance, tissuetemperature, output current and/or voltage, etc.). The controller 620then signals the power supply 627 and/or RF output stage 628 which thenadjusts the DC and/or RF power supply, respectively. The controller 620also receives input signals from the input controls of the generator 600and/or instrument 10. The controller 620 utilizes the input signals toadjust the power output of the generator 600 and/or instructs thegenerator 20 to perform other control functions.

The microprocessor 625 is capable of executing software instructions forprocessing data received by the sensor module 622, and for outputtingcontrol signals to the generator 600, accordingly. The softwareinstructions, which are executable by the controller 620, are stored inthe memory 626 of the controller 620.

The controller 620 may include analog and/or logic circuitry forprocessing the sensed values and determining the control signals thatare sent to the generator 600, rather than, or in combination with, themicroprocessor 625.

The sensor module 622 may include a plurality of sensors (not explicitlyshown) strategically located for sensing various properties orconditions, e.g., tissue impedance, voltage at the tissue site, currentat the tissue site, etc. The sensors are provided with leads (orwireless) for transmitting information to the controller 620. The sensormodule 622 may include control circuitry that receives information frommultiple sensors, and provides the information and the source of theinformation (e.g., the particular sensor providing the information) tothe controller 620.

More particularly, the sensor module 622 may include a real-time voltagesensing system (not explicitly shown) and a real-time current sensingsystem (not explicitly shown) for sensing real-time values related toapplied voltage and current at the surgical site. Additionally, an RMSvoltage sensing system (not explicitly shown) and an RMS current sensingsystem (not explicitly shown) may be included for sensing and derivingRMS values for applied voltage and current at the surgical site.

The generator 600 includes suitable input controls (e.g., buttons,activators, switches, touch screen, etc.) for controlling the generator600, as well as one or more display screens for providing the surgeonwith variety of output information (e.g., intensity settings, treatmentcomplete indicators, etc.). The controls allow the surgeon to adjustpower of the RF energy, waveform, and other parameters to achieve thedesired waveform suitable for a particular task (e.g., tissue ablation).Further, the instrument 10 may include a plurality of input controlswhich may be redundant with certain input controls of the generator 600.Placing the input controls at the instrument 10 allows for easier andfaster modification of RF energy parameters during the surgicalprocedure without requiring interaction with the generator 600.

A generator 600 according to the present disclosure can performmonopolar and bipolar electrosurgical procedures, including tissueablation procedures. The generator may include a plurality of outputsfor interfacing with various electrosurgical instruments (e.g., amonopolar active electrode, return electrode, bipolar electrosurgicalforceps, footswitch, etc.). Further, the generator includes electroniccircuitry configured for generating radio frequency power specificallysuited for various electrosurgical modes (e.g., cutting, blending,division, etc.) and procedures (e.g., monopolar, bipolar, vesselsealing).

Piezoelectric sensors 390 are configured to automatically sense thesealing pressure on the tissue disposed between the jaw members 110 and120 and provide feedback to controller 620 during the sealing process.Controller 620 may then regulate and adjust the closure pressure betweenthe jaw members 110 and 120 during the sealing process to enhance thetissue seal.

As seen in FIG. 6, piezoelectric sensors 390 may be coupled to thecontrol assembly via an open loop or closed loop feedback system toregulate the seal pressure on the tissue between the jaw members 110 and120. It is important to note that the closure pressure of the jawmembers 110 and 120 correlates to, but is not necessarily the same as,the sealing pressure on the tissue disposed between the jaw members 110and 120. The piezoelectric sensors 390 measure the sealing pressure onthe tissue and relay the sealing pressure information back to controller620 which operatively communicates with instrument 10 to adjust thesealing pressure based upon the information provided by piezoelectricsensors 390 and the desired sealing pressure according to apredetermined seal pressure profile.

Instrument 10 may include a pressure controller 630 that is operativelycoupled to the shaft 12 of the forceps 10. The pressure controller 630may be any type of electrical, or electro-mechanical mechanism thatadjusts the force on the drive assembly (not shown) to increase ordecrease the closure pressure of the jaw members 110 and 120 which, inturn, increases or decreases the seal pressure on the tissue disposedtherebetween. For example, a servo motor, gear assembly, hydraulicmechanism, worm drive, etc. may be coupled to the shaft 12 andoperatively coupled to the drive assembly (not shown) to provideadditional force to the drive assembly (not shown) as per theinformation.

As mentioned above, in one embodiment, the initial closure pressurebetween the jaw members 110 and 120 upon actuation of the handleassembly 30 and locking of the moveable handle 40 relative to the fixedhandle 50 is about 3 kg/cm² to about 16 kg/cm². The sealing pressure onthe tissue may or may not fall within this range. The piezoelectricsensors 390 may be configured to initially determine the sealingpressure on tissue prior to initial activation of the forceps. Forexample, the piezoelectric sensors 390 may determine that additionalforce needs to be provided to the drive assembly (not shown) to increasethe closure pressure of the jaw members 110 and 120 which, in turn,increases the sealing pressure of the tissue 400.

The appropriate sealing pressure for initial activation may be basedupon a predetermined pressure profile stored within memory 626, whichmay be based on tissue type, tissue temperature, tissue size, etc. Ifmore or less sealing pressure on tissue is required, controller 620communicates with the pressure controller 630 to regulate the closureforce of the jaw members 110 and 120. For example, while the handle 40is locked relative to fixed handle 50, the pressure controller may beconfigured to provide +/−10 kg/cm² when required to match apredetermined pressure profile or pressure algorithm.

During the sealing process, the piezoelectric sensors 390, controller620 and the pressure controller 630 all cooperate to regulate thesealing pressure on tissue to conform to a predetermined pressureprofile or pressure algorithm. For example, the pressure controller 630may be instructed by controller 620 to increase the closure pressure onthe jaw members 110 and 120 (which increases the sealing pressure ontissue 400) due to the tissue shrinking during the sealing process.Moreover, the seal pressure may be cycled during electrical activationbased upon a predetermined sinusoidal pressure profile to enhance thetissue seal. The piezoelectric sensors 390 may interact sequentially,simultaneously or in another manner to sense feedback from the tissueand determine the sealing pressure.

The procedure may be automated using a series of piezoelectric sensors390, controller 620 and pressure controller 630. The sealing pressurecontrol system described herein is believed to provide more effectivesealing of tissue especially large tissue structures, such as lungtissue. In the automated system, the sealing pressure on the tissue ismonitored and adjusted during activation based upon a continually-sensedsurgical condition from the piezoelectric sensors 390 utilizing an openor closed feed back control loop. The pressure controller 630 may bemanual, where the gauge instructs a user through a visual or audibleindicator to increase or decrease the closure pressure on the jaw to inturn adjust the sealing pressure on the tissue.

As shown in FIG. 7, a method for sealing tissue using the forceps 10 isalso disclosed herein that includes the initial step 602 of providing anelectrosurgical instrument, e.g., forceps 10, including one or moreshafts 12 having an end effector assembly 100 at a distal end thereof,the end effector assembly 100 including a pair of opposing jaw members110 and 120 movable from a first spaced apart position to a secondposition for grasping tissue. At least one jaw member, e.g., 110 isadapted to connect to an electrical energy source. In step 604, at leastone jaw member 110 is actuated to the second position for graspingtissue. The closing pressure between the jaw members is regulated bycontrolling the actuator in step 606. The instrument 10 senses a sealpressure of tissue 400 disposed between the jaw members 110 and 120 instep 608 and provides feedback to controller 620 regarding the sealpressure of tissue disposed between the jaw members 110 and 120. In step612, the pressure controller 630 adjusts the closing pressure toregulate the seal pressure of the jaw members 110 and 120 on the tissueduring the sealing process to within a predetermined range.

In one method, the seal pressure may be determined prior to initialactivation of the forceps, continually-sensed during the sealing processand/or after activation to determine seal quality. The seal pressure maybe regulated according to a seal pressure profile (e.g., sinusoidal) orseal pressure algorithm. Moreover, the seal pressure may be cycledduring electrical activation based upon a predetermined pressure profileor pressure algorithm.

The foregoing description is only illustrative of the presentdisclosure. Various alternatives and modifications can be devised bythose skilled in the art without departing from the disclosure.Accordingly, the present disclosure is intended to embrace all suchalternatives, modifications and variances. The embodiments describedwith reference to the attached figures are presented only to demonstratecertain examples of the disclosure. Other elements, steps, methods andtechniques that are insubstantially different from those described aboveand/or in the appended claims are also intended to be within the scopeof the disclosure.

1-8. (canceled)
 9. A method of constructing a jaw member for an endeffector assembly, the method comprising: creating a sealing plate byforming a stainless steel layer into the sealing plate; applying a firstmask to the stainless steel layer, wherein the first mask exposes aportion of the stainless steel layer; etching the exposed portion ofstainless steel layer to create at least one hole in the stainless steellayer and removing the mask; creating an insulative plate by: providinga plastic substrate; adhering a conductive layer to the plasticsubstrate; applying a second mask to the conductive layer, wherein thesecond mask exposes a portion of the conductive layer to outline atleast one circuit trace and at least one contact; and etching theexposed portion the conductive layer and removing the mask; providing asupport base; attaching the insulative plate to the support base;attaching the sealing plate on top of the insulative plate so that theat least one hole of the sealing plate overlaps the at least one contactof the insulative plate; and coupling a piezoelectric sensor to the atleast one contact of the insulative plate.
 10. The method according toclaim 9, wherein the piezoelectric sensor is disposed in the at leastone hole of the sealing plate.
 11. The method according to claim 9,wherein the piezoelectric sensor is raised relative to the sealing plateand is configured to create a gap between opposed sealing plates of thejaw members.